Inhibition of glycogen synthase kinase 3beta (GSK3beta) decreases inflammatory responses in brain endothelial cells

Glycogen synthase kinase 3 activity enhances liver inflammation in MASH

Background & Aims

Metabolic dysfunction-associated steatohepatitis (MASH) is characterized by excessive circulating toxic lipids, hepatic steatosis, and liver inflammation. Monocyte adhesion to liver sinusoidal endothelial cells (LSECs) and transendothelial migration (TEM) are crucial in the inflammatory process. Under lipotoxic stress, LSECs develop a proinflammatory phenotype known as endotheliopathy. However, mediators of endotheliopathy remain unclear.

Methods

Primary mouse LSECs isolated from C57BL/6J mice fed chow or MASH-inducing diets rich in fat, fructose, and cholesterol (FFC) were subjected to multi-omics profiling. Mice with established MASH resulting from a choline-deficient high-fat diet (CDHFD) or FFC diet were also treated with two structurally distinct GSK3 inhibitors (LY2090314 and elraglusib [9-ING-41]).

Results

Integrated pathway analysis of the mouse LSEC proteome and transcriptome indicated that leukocyte TEM and focal adhesion were the major pathways altered in MASH. Kinome profiling of the LSEC phosphoproteome identified glycogen synthase kinase (GSK)-3β as the major kinase hub in MASH. GSK3β-activating phosphorylation was increased in primary human LSECs treated with the toxic lipid palmitate and in human MASH. Palmitate upregulated the expression of C-X-C motif chemokine ligand 2, intracellular adhesion molecule 1, and phosphorylated focal adhesion kinase, via a GSK3-dependent mechanism. Congruently, the adhesive and transendothelial migratory capacities of primary human neutrophils and THP-1 monocytes through the LSEC monolayer under lipotoxic stress were reduced by GSK3 inhibition. Treatment with the GSK3 inhibitors LY2090314 and elraglusib ameliorated liver inflammation, injury, and fibrosis in FFC- and CDHFD-fed mice, respectively. Immunophenotyping using cytometry by mass cytometry by time of flight of intrahepatic leukocytes from CDHFD-fed mice treated with elraglusib showed reduced infiltration of proinflammatory monocyte-derived macrophages and monocyte-derived dendritic cells.

Conclusion

GSK3 inhibition attenuates lipotoxicity-induced LSEC endotheliopathy and could serve as a potential therapeutic strategy for treating human MASH.

Impact and Implications

LSECs under lipotoxic stress in MASH develop a proinflammatory phenotype known as endotheliopathy, with obscure mediators and functional outcomes. The current study identified GSK3 as the major driver of LSEC endotheliopathy, examined its pathogenic role in myeloid cell-associated liver inflammation, and defined the therapeutic efficacy of pharmacological GSK3 inhibitors in murine MASH. This study provides preclinical data for the future investigation of GSK3 pharmacological inhibitors in human MASH. The results of this study are important to hepatologists, vascular biologists, and investigators studying the mechanisms of inflammatory liver disease and MASH, as well as those interested in drug development.

Genetic and Pharmacological Modulation of P75 Neurotrophin Receptor Attenuate Brain Damage After Ischemic Stroke in Mice

The precursor nerve growth factor (ProNGF) and its receptor p75 neurotrophin receptor (p75NTR) are upregulated in several brain diseases, including ischemic stroke. The activation of p75NTR is associated with neuronal apoptosis and inflammation. Thus, we hypothesized that p75NTR modulation attenuates brain damage and improves functional outcomes after ischemic stroke. Two sets of experiments were performed. (1) Adult wild-type (WT) C57BL/6 J mice were subjected to intraluminal suture-middle cerebral artery occlusion (MCAO) to induce cerebral ischemia. Pharmacological inhibitor of p75NTR, LM11A-31 (50 mg/kg), or normal saline was administered intraperitoneally (IP) 1 h post-MCAO, and animals survived for 24 h. (2) Adult p75NTR heterozygous knockout (p75NTR+/-) and WT were subjected to photothrombotic (pMCAO) to induce ischemic stroke, and the animals survived for 72 h. The sensory-motor function of animals was measured using Catwalk XT. The brain samples were collected to assess infarction volume, edema, hemorrhagic transformation, neuroinflammation, and signaling pathway at 24 and 72 h after the stroke. The findings described that pharmacological inhibition and genetic knocking down of p75NTR reduce infarction size, edema, and hemorrhagic transformation following ischemic stroke. Additionally, p75NTR modulation significantly decreased several anti-apoptosis markers and improved sensory motor function compared to the WT mice following ischemic stroke. Our observations exhibit that the involvement of p75NTR in ischemic stroke and modulation of p75NTR could improve the outcome of ischemic stroke by increasing cell survival and enhancing motor performance. LM11A-31 has the potential to be a promising therapeutic agent for ischemic stroke. However, more evidence is needed to illuminate the efficacy of LM11A-31 in ischemic stroke.

Intravital Microscopy of Lipopolysaccharide-Induced Inflammatory Changes in Different Organ Systems-A Scoping Review

Intravital microscopy (IVM) is a powerful imaging tool that captures biological processes in real-time. IVM facilitates the observation of complex cellular interactions in vivo, where ex vivo and in vitro experiments lack the physiological environment. IVM has been used in a multitude of studies under healthy and pathological conditions in different organ systems. IVM has become essential in the characterization of the immune response through visualization of leukocyte-endothelial interactions and subsequent changes within the microcirculation. Lipopolysaccharide (LPS), a common inflammatory trigger, has been used to induce inflammatory changes in various studies utilizing IVM. In this review, we provide an overview of IVM imaging of LPS-induced inflammation in different models, such as the brain, intestines, bladder, and lungs.

Barrier-environment interactions along the gut-brain axis and their influence on cognition and behaviour throughout the lifespan

Environment is known to substantially alter mental state and behaviour across the lifespan. Biological barriers such as the blood-brain barrier (BBB) and gut barrier (GB) are major hubs for communication of environmental information. Alterations in the structural, social and motor environment at different stages of life can influence function of the BBB and GB and their integrity to exert behavioural consequences. Importantly, each of these environmental components is associated with a distinct immune profile, glucocorticoid response and gut microbiome composition, creating unique effects on the BBB and GB. These barrier-environment interactions are sensitive to change throughout life, and positive or negative alterations at critical stages of development can exert long-lasting cognitive and behavioural consequences. Furthermore, because loss of barrier integrity is implicated in pathogenesis of mental disorders, the pathways of environmental influence represent important areas for understanding these diseases. Positive environments can be protective against stress- and age-related damage, raising the possibility of novel pharmacological targets. This review summarizes known mechanisms of environmental influence - such as social interactions, structural complexity and physical exercise - on barrier composition, morphology and development, and considers the outcomes and implications of these interactions in the context of psychiatric disorders.

Glycogen Synthase Kinase 3β Involvement in Neuroinflammation and Neurodegenerative Diseases

BACKGROUND

GSK-3β activity has been strictly related to neuroinflammation and neurodegeneration. Alzheimer's disease is the most studied neurodegenerative disease, but GSK-3β seems to be involved in almost all neurodegenerative diseases including Parkinson's disease, amyotrophic lateral sclerosis, frontotemporal dementia, Huntington's disease and the autoimmune disease multiple sclerosis.

OBJECTIVE

The aim of this review is to help researchers both working on this research topic or not to have a comprehensive overview on GSK-3β in the context of neuroinflammation and neurodegeneration.

METHOD

Literature has been searched using PubMed and SciFinder databases by inserting specific keywords. A total of more than 500 articles have been discussed.

RESULTS

First of all, the structure and regulation of the kinase were briefly discussed and then, specific GSK-3β implications in neuroinflammation and neurodegenerative diseases were illustrated also with the help of figures, to conclude with a comprehensive overview on the most important GSK-3β and multitarget inhibitors. For all discussed compounds, the structure and IC50 values at the target kinase have been reported.

CONCLUSION

GSK-3β is involved in several signaling pathways both in neurons as well as in glial cells and immune cells. The fine regulation and interconnection of all these pathways are at the base of the rationale use of GSK-3β inhibitors in neuroinflammation and neurodegeneration. In fact, some compounds are now under clinical trials. Despite this, pharmacodynamic and ADME/Tox profiles of the compounds were often not fully characterized and this is deleterious in such a complex system.

The Blood-Brain Barrier: Much More Than a Selective Access to the Brain

The blood-brain barrier is a dynamic structure, collectively referred to as the neurovascular unit. It is responsible for the exchange of blood, oxygen, ions, and other molecules between the peripheral circulation and the brain compartment. It is the main entrance to the central nervous system and as such critical for the maintenance of its homeostasis. Dysfunction of the blood-brain barrier is a characteristic of several neurovascular pathologies. Moreover, physiological changes, environmental factors, nutritional habits, and psychological stress can modulate the tightness of the barrier. In this contribution, we summarize our current understanding of structure and function of this important component of the brain. We also describe the neurological deficits associated with its damage. A special emphasis is placed in the effect of the exposure to xenobiotics and pollutants in the permeability of the barrier. Finally, current protective strategies as well as the culture models to study this fascinating structure are discussed.

Real-Time Imaging of Immune Modulation by Cannabinoids Using Intravital Fluorescence Microscopy

Introduction: The endocannabinoid system (ECS) is an endogenous regulatory system involved in a wide range of physiologic and disease processes. Study of ECS regulation provides novel drug targets for disease treatment. Intravital microscopy (IVM), a microscopy-based imaging method that allows the observation of cells and cell-cell interactions within various tissues and organs in vivo, has been utilized to study tissues and cells in their physiologic microenvironment. This article reviews the current state of the IVM techniques used in ECS-related inflammation research. Methodological Aspects of IVM: IVM with focus on conventional fluorescent microscope has been introduced in investigation of microcirculatory function and the behavior of individual circulating cells in an in vivo environment. Experimental setting, tissue protection under physiologic condition, and microscopical observation are described. Application of IVM in Experimental Inflammatory Disorders: Using IVM to investigate the effects of immune modulation by cannabinoids is extensively reviewed. The inflammatory disorders include sepsis, arthritis, diabetes, interstitial cystitis, and inflammatory conditions in the central nervous system and eyes. Conclusion: IVM is a critical tool in cannabinoid and immunology research. It has been applied to investigate the role of the ECS in physiologic and disease processes. This review demonstrates that the IVM technique provides a unique means in understanding ECS regulation on immune responses in diseases under their physical conditions, which could not be achieved by other methods.

The role of brain barriers in the neurokinetics and pharmacodynamics of lithium

Lithium (Li) is the most widely used mood stabilizer in treating patients with bipolar disorder. However, more than half of the patients do not or partially respond to Li therapy, despite serum Li concentrations in the serum therapeutic range. The exact mechanisms underlying the pharmacokinetic-pharmacodynamic (PK-PD) relationships of lithium are still poorly understood and alteration in the brain pharmacokinetics of lithium may be one of the mechanisms explaining the variability in the clinical response to Li. Brain barriers such as the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) play a crucial role in controlling blood-to-brain and brain-to-blood exchanges of various molecules including central nervous system (CNS) drugs. Recent in vivo studies by nuclear resonance spectroscopy revealed heterogenous brain distribution of Li in human that were not always correlated with serum concentrations, suggesting regional and variable transport mechanisms of Li through the brain barriers. Moreover, alteration in the functionality and integrity of brain barriers is reported in various CNS diseases, as a cause or a consequence and in this regard, Li by itself is known to modulate BBB properties such as the expression and activity of various transporters, metabolizing enzymes, and the specialized tight junction proteins on BBB. In this review, we will focus on recent knowledge into the role of the brain barriers as key-element in the Li neuropharmacokinetics which might improve the understanding of PK-PD of Li and its interindividual variability in drug response.

Molecular Biology of Atherosclerotic Ischemic Strokes

Among the causes of global death and disability, ischemic stroke (also known as cerebral ischemia) plays a pivotal role, by determining the highest number of worldwide mortality, behind cardiomyopathies, affecting 30 million people. The etiopathogenetic burden of a cerebrovascular accident could be brain ischemia (~80%) or intracranial hemorrhage (~20%). The most common site when ischemia occurs is the one is perfused by middle cerebral arteries. Worse prognosis and disablement consequent to brain damage occur in elderly patients or affected by neurological impairment, hypertension, dyslipidemia, and diabetes. Since, in the coming years, estimates predict an exponential increase of people who have diabetes, the disease mentioned above constitutes together with stroke a severe social and economic burden. In diabetic patients after an ischemic stroke, an exorbitant activation of inflammatory molecular pathways and ongoing inflammation is responsible for more severe brain injury and impairment, promoting the advancement of ischemic stroke and diabetes. Considering that the ominous prognosis of ischemic brain damage could by partially clarified by way of already known risk factors the auspice would be modifying poor outcome in the post-stroke phase detecting novel biomolecules associated with poor prognosis and targeting them for revolutionary therapeutic strategies.

Azolo[d]pyridazinones in medicinal chemistry

Azolo[d]pyridazinone is a privileged structure and versatile pharmacophore whose derivatives are associated with diverse biological activities, in particular antidiabetic, antiasthmatic, anticancer, analgesic, anti-inflammatory, antithrombotic, antidepressant and antimicrobial activities. The importance of this scaffold against some targets like PDE, COX and DPP-4 has been reviewed in detail previously. In the present review, we have summarized comprehensive information on azolo[d]pyridazinone derivatives investigated by many researchers for their diverse pharmacological activities, structure-activity relationship and molecular modeling studies since 2000. The review may lead scientists in the research fields of organic synthesis, medicinal chemistry and pharmacology to the strategic design and development of azolo[d]pyridazinone-based drug candidates in the future.

Antiviral Activity of Belladonna During Japanese Encephalitis Virus Infection via Inhibition of Microglia Activation and Inflammation Leading to Neuronal Cell Survival

Japanese encephalitis virus (JEV) is the main cause of viral encephalitis resulting in more than 68 000 clinical cases every year with case fatality rate as high as 30-40% for which no specific treatments are available. We have recently exhibited belladonna may be widely applicable for the treatment of various neurological disorders. Therefore, we developed a hydroalcoholic formulation of belladonna (B200) consisting of atropine and scopolamine and showed its antiviral efficacy against JEV infection. B200 treatment increases neuronal cell survival by reducing JEV induced cytopathic effects which were evident from significant reduction in necrotic cell population by flow-cytometry analysis and caspase 3 and 8 enzymatic activities. B200 treatment was found to reduce the intracellular JEV level observed by significant reduction in JEV-fluorescein isothiocyanate (FITC) expression in both neurons and microglia. Because microglia plays a crucial role in JEV pathogenesis, we further investigated the anti-JEV effects of B200 on human microglia cells and elucidated the mechanism of action by performing whole-transcriptome sequencing. Gene expression analysis revealed that B200 reduces the pro-apoptotic and inflammatory gene expression observed by significant reduction in BAD, BAX, CASP3, CASP8, IL1B, and CXCL10 and increase in IL10 responsive gene expression. Interestingly, our molecular docking analysis revealed that atropine and scopolamine interact with the His288 residue of NS3 protein, a crucial residue for RNA unwinding and ATPase activity that was further confirmed by degradation of NS3 protein. Drug likeness, ADME (absorption, distribution, metabolism, and excretion), and toxicity analysis further suggests that atropine and scopolamine both cross the blood-brain barrier, which is crucial for effective treatment of Japanese encephalitis (JE).

Repairing blood-CNS barriers: Future therapeutic approaches for neuropsychiatric disorders

Central nervous system (CNS) drug development faces significant difficulties that translate into high rates of failure and lack of innovation. The pathophysiology of neurological and psychiatric disorders often results in the breakdown of blood-CNS barriers, disturbing the CNS microenvironment and worsening disease progression. Therefore, restoring the integrity of blood-CNS barriers may have a beneficial influence in several CNS disorders and improve treatment outcomes. In this review, pathways that may be modulated to protect blood-CNS barriers from neuroinflammatory and oxidative insults are featured. First, the participation of the brain endothelium and glial cells in disruption processes is discussed. Then, the relevance of regulatory systems is analysed, specifically the hypothalamic-pituitary axis, the renin-angiotensin system, sleep and circadian rhythms, and glutamate neurotransmission. Lastly, compounds of endogenous and exogenous origin that are known to mediate the repair of blood-CNS barriers are presented. We believe that enhancing the protection of blood-CNS barriers is a promising therapeutic strategy to pursue in the future.

miR-98 reduces endothelial dysfunction by protecting blood-brain barrier (BBB) and improves neurological outcomes in mouse ischemia/reperfusion stroke model

Most neurological diseases, including stroke, lead to some degree of blood-brain barrier (BBB) dysfunction. A significant portion of BBB injury is caused by inflammation, due to pro-inflammatory factors produced in the brain, and by leukocyte engagement of the brain endothelium. Recently, microRNAs (miRNAs) have appeared as major regulators of inflammation-induced changes to gene expression in the microvascular endothelial cells (BMVEC) that comprise the BBB. However, miRNAs' role during cerebral ischemia/reperfusion is still underexplored. Endothelial levels of miR-98 were significantly altered following ischemia/reperfusion insults, both in vivo and in vitro, transient middle cerebral artery occlusion (tMCAO), and oxygen-glucose deprivation (OGD), respectively. Overexpression of miR-98 reduced the mouse's infarct size after tMCAO. Further, miR-98 lessened infiltration of proinflammatory Ly6C^HI leukocytes into the brain following stroke and diminished the prevalence of M1 (activated) microglia within the impacted area. miR-98 attenuated BBB permeability, as demonstrated by changes to fluorescently-labeled dextran penetration in vivo and improved transendothelial electrical resistance (TEER) in vitro. Treatment with miR-98 improved significantly the locomotor impairment. Our study provides identification and functional assessment of miRNAs in brain endothelium and lays the groundwork for improving therapeutic approaches for patients suffering from ischemic attacks.

In vitro modeling of blood-brain barrier and interface functions in neuroimmune communication

Neuroimmune communication contributes to both baseline and adaptive physiological functions, as well as disease states. The vascular blood-brain barrier (BBB) and associated cells of the neurovascular unit (NVU) serve as an important interface for immune communication between the brain and periphery through the blood. Immune functions and interactions of the BBB and NVU in this context can be categorized into at least five neuroimmune axes, which include (1) immune modulation of BBB impermeability, (2) immune regulation of BBB transporters, secretions, and other functions, (3) BBB uptake and transport of immunoactive substances, (4) immune cell trafficking, and (5) BBB secretions of immunoactive substances. These axes may act separately or in concert to mediate various aspects of immune signaling at the BBB. Much of what we understand about immune axes has been from work conducted using in vitro BBB models, and recent advances in BBB and NVU modeling highlight the potential of these newer models for improving our understanding of how the brain and immune system communicate. In this review, we discuss how conventional in vitro models of the BBB have improved our understanding of the 5 neuroimmune axes. We further evaluate the existing literature on neuroimmune functions of novel in vitro BBB models, such as those derived from human induced pluripotent stem cells (iPSCs) and discuss their utility in evaluating aspects of neuroimmune communication.

GSK-3β/mTORC1 Couples Synaptogenesis and Axonal Repair to Reduce Hypoxia Ischemia-Mediated Brain Injury in Neonatal Rats

Glycogen synthase kinase 3 beta (GSK-3β) plays an important role in neurological outcomes after brain injury. However, its roles and mechanisms in hypoxia-ischemia (HI) are unclear. Activation of mTOR complex 1 (mTORC1) has been proven to induce the synthesis of proteins associated with regeneration. We hypothesized that GSK-3β inhibition could activate the mTORC1 signaling pathway, which may reduce axonal injury and induce synaptic protein synthesis and functional recovery of synapses after HI. By analyzing a P7 rat model of cerebral HI and an in vitro ischemic (oxygen glucose deprivation) model, we found that GSK-3β inhibitors (GSK-3β siRNA or lithium chloride) activated mTORC1 signaling, leading to increased expression of synaptic proteins, including synapsin 1, PSD95, and GluR1, and the microtubule-associated protein Tau and decreased expression of the axonal injury-associated protein amyloid precursor protein. These changes contributed to attenuated axonal injury (decreased amyloid precursor protein staining and axonal loss by silver staining), improved electrophysiological properties of synapses, and enhanced spatial memory performance in the Morris water maze. However, inhibition of mTORC1 by rapamycin blocked the benefits induced by GSK-3β inhibition, suggesting that GSK-3β inhibition induces synaptogenesis and axonal repair via mTORC1 signaling, which may benefit neonatal rats subjected to HI.

sVCAM-1, sICAM-1, TNF-α and IL-6 levels in bipolar disorder type I: Acute, longitudinal and therapeutic implications

OBJECTIVES

To explore the serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular cell adhesion molecule-1 (sICAM-1), tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in patients with bipolar disorder (BD), with regard to acute episode characteristics, course of the disorder and treatment.

METHODS

The study group consisted of 83 patients diagnosed with BD type I. The control group consisted of 73 healthy individuals, matched with the study group according to age, gender and body mass index. The serum levels of sVCAM-1, sICAM-1, TNF-α and IL-6 were measured by ELISA.

RESULTS

Compared with healthy controls, significantly elevated levels of IL-6 and sICAM-1 and significantly lower levels of TNF-α and sVCAM-1 were identified in acute and remission phases of BD. The acute serum levels of sVCAM-1 were associated with the type and severity of acute mood symptoms as well as with course of illness characteristics. TNF-α was associated with duration of untreated disorder and type of treatment.

CONCLUSIONS

BD is related to both acute and long-term alterations of immune mediators, including adhesion molecules. The potential immunomodulatory role of pharmacotherapeutic treatment is also to be considered in BD.

Forkhead box O1 (FOXO1) controls the migratory response of Toll-like receptor (TLR3)-stimulated human mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) can potently regulate the functions of immune cells and are being investigated for the management of inflammatory diseases. Toll-like receptor 3 (TLR3)-stimulated human MSCs (hMSCs) exhibit increased migration and chemotaxis within and toward damaged tissues. However, the regulatory mechanisms underlying these migratory activities are unclear. Therefore, we analyzed the migration capability and gene expression profiles of TLR3-stimulated hMSCs using RNA-Seq, wound healing, and transwell cell migration assay. Along with increased cell migration, the TLR3 stimulation also increased the expression of cytokines, chemokines, and cell migration-related genes. The promoter regions of the latter showed an enrichment of putative motifs for binding the transcription factors forkhead box O1 (FOXO1), FOXO3, NF-κB (NF-κB1), and RELA proto-oncogene and NF-κB subunit. Of note, FOXO1 inhibition by the FOXO1-selective inhibitor AS1842856 significantly reduced both migration and the expression of migration-related genes. In summary, our results indicate that TLR3 stimulation induces hMSC migration through the expression of FOXO1-activated genes.

Recent Expansions on Cellular Models to Uncover the Scientific Barriers Towards Drug Development for Alzheimer's Disease

Globally, the central nervous system (CNS) disorders appear as the most critical pathological threat with no proper cure. Alzheimer's disease (AD) is one such condition frequently observed with the aged population and sometimes in youth too. Most of the research utilizes different animal models for in vivo study of AD pathophysiology and to investigate the potency of the newly developed therapy. These in vivo models undoubtably provide a powerful investigation tool to study human brain. Although, it sometime fails to mimic the exact environment and responses as the human brain owing to the distinctive genetic and anatomical features of human and rodent brain. In such condition, the in vitro cell model derived from patient specific cell or human cell lines can recapitulate the human brain environment. In addition, the frequent use of animals in research increases the cost of study and creates various ethical issues. Instead, the use of in vitro cellular models along with animal models can enhance the translational values of in vivo models and represent a better and effective mean to investigate the potency of therapeutics. This strategy also limits the excessive use of laboratory animal during the drug development process. Generally, the in vitro cell lines are cultured from AD rat brain endothelial cells, the rodent models, human astrocytes, human brain capillary endothelial cells, patient derived iPSCs (induced pluripotent stem cells) and also from the non-neuronal cells. During the literature review process, we observed that there are very few reviews available which describe the significance and characteristics of in vitro cell lines, for AD investigation. Thus, in the present review article, we have compiled the various in vitro cell lines used in AD investigation including HBMEC, BCECs, SHSY-5Y, hCMEC/D3, PC-2 cell line, bEND3 cells, HEK293, hNPCs, RBE4 cells, SK-N-MC, BMVECs, CALU-3, 7W CHO, iPSCs and cerebral organoids cell lines and different types of culture media such as SCM, EMEM, DMEM/F12, RPMI, EBM and 3D-cell culture.

Blood-brain barrier permeability and physical exercise

In this narrative review, a theoretical framework on the crosstalk between physical exercise and blood-brain barrier (BBB) permeability is presented. We discuss the influence of physical activity on the factors affecting BBB permeability such as systemic inflammation, the brain renin-angiotensin and noradrenergic systems, central autonomic function and the kynurenine pathway. The positive role of exercise in multiple sclerosis and Alzheimer’s disease is described. Finally, the potential role of conditioning as well as the effect of exercise on BBB tight junctions is outlined. There is a body of evidence that regular physical exercise diminishes BBB permeability as it reinforces antioxidative capacity, reduces oxidative stress and has anti-inflammatory effects. It improves endothelial function and might increase the density of brain capillaries. Thus, physical training can be emphasised as a component of prevention programs developed for patients to minimise the risk of the onset of neuroinflammatory diseases as well as an augmentation of existing treatment. Unfortunately, despite a sound theoretical background, it remains unclear as to whether exercise training is effective in modulating BBB permeability in several specific diseases. Further research is needed as the impact of exercise is yet to be fully elucidated.

A Peptide Targeting Inflammatory CNS Lesions in the EAE Rat Model of Multiple Sclerosis

Multiple sclerosis is characterized by inflammatory lesions dispersed throughout the central nervous system (CNS) leading to severe neurological handicap. Demyelination, axonal damage, and blood brain barrier alterations are hallmarks of this pathology, whose precise processes are not fully understood. In the experimental autoimmune encephalomyelitis (EAE) rat model that mimics many features of human multiple sclerosis, the phage display strategy was applied to select peptide ligands targeting inflammatory sites in CNS. Due to the large diversity of sequences after phage display selection, a bioinformatics procedure called "PepTeam" designed to identify peptides mimicking naturally occurring proteins was used, with the goal to predict peptides that were not background noise. We identified a circular peptide CLSTASNSC called "Ph48" as an efficient binder of inflammatory regions of EAE CNS sections including small inflammatory lesions of both white and gray matter. Tested on human brain endothelial cells hCMEC/D3, Ph48 was able to bind efficiently when these cells were activated with IL1β to mimic inflammatory conditions. The peptide is therefore a candidate for further analyses of the molecular alterations in inflammatory lesions.

Characterization of human fetal brain endothelial cells reveals barrier properties suitable for in vitro modeling of the BBB with syngenic co-cultures

Endothelial cells (ECs) form the basis of the blood-brain barrier (BBB), a physical barrier that selectively restricts transport into the brain. In vitro models can provide significant insight into BBB physiology, mechanisms of human disease pathology, toxicology, and drug delivery. Given the limited availability of primary human adult brain microvascular ECs ( aBMVECs), human fetal tissue offers a plausible alternative source for multiple donors and the opportunity to build syngenic tri-cultures from the same host. Previous efforts to culture fetal brain microvascular ECs ( fBMVECs) have not been successful in establishing mature barrier properties. Using optimal gestational age for isolation and flow cytometry cell sorting, we show for the first time that fBMVECs demonstrate mature barrier properties. fBMVECs exhibited similar functional phenotypes when compared to aBMVECs for barrier integrity, endothelial activation, and gene/protein expression of tight junction proteins and transporters. Importantly, we show that tissue used to culture fBMVECs can also be used to generate a syngenic co-culture, creating a microfluidic BBB on a chip. The findings presented provide a means to overcome previous challenges that limited successful barrier formation by fBMVECs. Furthermore, the source is advantageous for autologous reconstitution of the neurovascular unit for next generation in vitro BBB modeling.

The deubiquitinating enzyme USP48 stabilizes TRAF2 and reduces E-cadherin-mediated adherens junctions

The tumor necrosis factor receptor-associated factor 2 (TRAF2) is a second messenger adaptor protein that plays an essential role in propagating TNF-α-mediated signaling pathways. Modulation of TRAF2 activity by ubiquitination is well studied; however, the deubiquitinating enzyme (DUB), which regulates TRAF2 stability, has not been identified. Here we reveal USP48 as the first identified DUB to deubiquitinate and stabilize TRAF2 in epithelial cells. Down-regulation of USP48 increases K48-linked polyubiquitination of TRAF2 and reduces TRAF2 protein levels. Interestingly, USP48 only targets the TRAF2 related to JNK pathway, not the TRAF2 related to NF-κB and p38 pathways. USP48 is serine phosphorylated in response to TNF-α. The phosphorylation is catalyzed by glycogen synthase kinase 3β (GSK3β), ultimately resulting in increases in USP48 DUB activity. Furthermore, we reveal a new biologic function of TRAF2 that contributes to epithelial barrier dysfunction, which is attenuated by knockdown of USP48. Inhibition of TRAF2/JNK pathway increases E (epithelial)-cadherin expression and enhances epithelial barrier integrity, while knockdown of USP48 attenuates TNF-α/JNK pathway and increases E-cadherin expression and cell-cell junction in epithelial cells. These data, taken together, indicate that USP48 stabilizes TRAF2, which is promoted by GSK3β-mediated phosphorylation. Further, down-regulation of USP48 increases E-cadherin expression and epithelial barrier integrity through reducing TRAF2 stability.-Li, S., Wang, D., Zhao, J., Weathington, N. M., Shang, D., Zhao, Y. The deubiquitinating enzyme USP48 stabilizes TRAF2 and reduces E-cadherin-mediated adherens junctions.

Proteomics landscape of radiation-induced cardiovascular disease: somewhere over the paradigm

INTRODUCTION

Epidemiological studies clearly show that thoracic or whole body exposure to ionizing radiation increases the risk of cardiac morbidity and mortality. Radiation-induced cardiovascular disease (CVD) has been intensively studied during the last ten years but the underlying molecular mechanisms are still poorly understood. Areas covered: Heart proteomics is a powerful tool holding promise for the future research. The central focus of this review is to compare proteomics data on radiation-induced CVD with data arising from proteomics of healthy and diseased cardiac tissue in general. In this context we highlight common and unique features of radiation-related and other heart pathologies. Future prospects and challenges of the field are discussed. Expert commentary: Data from comprehensive cardiac proteomics have deepened the knowledge of molecular mechanisms involved in radiation-induced cardiac dysfunction. State-of-the-art proteomics has the potential to identify novel diagnostic and therapeutic markers of this disease.

ECIS technology reveals that monocytes isolated by CD14+ve selection mediate greater loss of BBB integrity than untouched monocytes, which occurs to a greater extent with IL-1β activated endothelium in comparison to TNFα

Background

We have previously shown that TNFα and IL-1β differentially regulate the inflammatory phenotype of human brain endothelial cells (hCMVECs). In this regard, IL-1β treatment was considerably more potent than TNFα at increasing expression of inflammatory chemokines and leukocyte adhesion molecules. We therefore hypothesised that interaction of the hCMVECs with human monocytes would also be dependent on the activation status of the endothelium. Therefore, the primary aim of this study was to assess whether brain endothelial cells activated by IL-1β or TNFα differed in their interaction with monocytes.

Methods

Monocyte interaction was measured using the real time, label-free impedance based ECIS technology, to evaluate endothelial barrier integrity during monocyte attachment and transendothelial migration.

Results

ECIS technology revealed that there was a greater loss of barrier integrity with IL-1β activation and this loss lasted for longer. This was expected and consistent with our hypothesis. However, more striking and concerning was the observation that the method of monocyte enrichment greatly influenced the extent of endothelial barrier compromise. Importantly, we observed that positively isolated monocytes (CD14^+ve) caused greater reduction in barrier resistance, than the negatively selected monocytes (untouched). Analysis of the isolated monocyte populations revealed that the CD14^+ve isolation consistently yields highly pure monocytes (>92%), whereas the untouched isolation was much more variable, yielding ~70% enrichment on average. These two enrichment methods were compared as it was thought that the presence of non-classical CD16^hi monocytes in the untouched enrichment may mediate greater compromise than the classical CD14^hi monocytes. This however, was not the case and these observations raise a number of important considerations pertaining to the enrichment strategy, which are essential for generating reliable and consistent data.

Conclusions

We conclude that IL-1β and TNFα differentially influence monocyte interaction with brain endothelial cells and moreover, the enrichment method also influences the monocyte response as revealed using ECIS technology.

Role of glycogen synthase kinase 3 in ischemia-induced blood-brain barrier disruption in aged female rats

Estrogen receptors have protective effects against ischemic brain injury. However, the molecular mechanisms underlying this phenomenon have yet to be well studied. Given that inhibition of glycogen synthase kinase (GSK3) can reduce cerebral ischemia/reperfusion injury, we hypothesized that estrogen receptors-mediated protective effects against ischemia-induced blood-brain barrier (BBB) disruption involve inhibition of GSK3. Thus, we evaluated GSK3 expression in the brain of ovariectomized female rats, and examined the effects of intracerebroventricular pre-treatments of SB216763, GSK3 inhibitor, on BBB permeability following middle cerebral artery occlusion (MCAO). We also examined the role of specific estrogen receptor subtype in regulation of GSK3 expression and BBB permeability after MCAO. We found that ovariectomized female rats exhibited increased mRNA levels of estrogen receptor α (ERα) and estrogen receptor β (ERβ), and increased protein levels of GSK3β but not GSK3α in brain cortical areas. Furthermore, intracerebroventricular pre-treatments of SB216763 dose-dependently attenuated brain infarction volume, brain water contents, neurological deficits, and BBB disruption, and increased tight junction protein ZO-1 and occludin expression at 24 h following MCAO. Finally, activation of ERβ but not ERα dose-dependently decreased GSK3β expression at 24 h following MCAO. This was associated with increased tight junction protein expression and improved neurological scores. Thus, our study suggested that activation of ERβ may protect against brain ischemia-induced BBB disruption by inhibiting GSK3β-mediated signaling.

Potential involvement of glycogen synthase kinase (GSK)-3β in a rat model of multiple sclerosis: evidenced by lithium treatment

Glycogen synthase kinase (GSK)-3β has been known as a pro-inflammatory molecule in neuroinflammation. The involvement of GSK-3β remains unsolved in acute monophasic rat experimental autoimmune encephalomyelitis (EAE). The aim of this study was to evaluate a potential role of GSK-3β in central nervous system (CNS) autoimmunity through its inhibition by lithium. Lithium treatment significantly delayed the onset of EAE paralysis and ameliorated its severity. Lithium treatment reduced the serum level of pro-inflammatory tumor necrosis factor a but not that of interleukin 10. Western blot analysis showed that the phosphorylation of GSK-3β (p-GSK-3β) and its upstream factor Akt was significantly increased in the lithium-treated group. Immunohistochemical examination revealed that lithium treatment also suppressed the activation of ionized calcium binding protein-1-positive microglial cells and vascular cell adhesion molecule-1 expression in the spinal cords of lithium-treated EAE rats. These results demonstrate that lithium ameliorates clinical symptom of acute monophasic rat EAE, and GSK-3 is a target for the suppression of acute neuroinflammation as far as rat model of human CNS disease is involved.

Gsk3 Signalling and Redox Status in Bipolar Disorder: Evidence from Lithium Efficacy

Objective. To discuss the link between glycogen synthase kinase-3 (GSK3) and the main biological alterations demonstrated in bipolar disorder (BD), with special attention to the redox status and the evidence supporting the efficacy of lithium (a GSK3 inhibitor) in the treatment of BD. Methods. A literature research on the discussed topics, using Pubmed and Google Scholar, has been conducted. Moreover, a manual selection of interesting references from the identified articles has been performed. Results. The main biological alterations of BD, pertaining to inflammation, oxidative stress, membrane ion channels, and circadian system, seem to be intertwined. The dysfunction of the GSK3 signalling pathway is involved in all the aforementioned "biological causes" of BD. In a complex scenario, it can be seen as the common denominator linking them all. Lithium inhibition of GSK3 could, at least in part, explain its positive effect on these biological dysfunctions and its superiority in terms of clinical efficacy. Conclusions. Deepening the knowledge on the molecular bases of BD is fundamental to identifying the biochemical pathways that must be targeted in order to provide patients with increasingly effective therapeutic tools against an invalidating disorder such as BD.

miRNAs Participate in MS Pathological Processes and Its Therapeutic Response

Multiple sclerosis is the most common autoimmune disease of the central nervous system. It is believed that the increased migration of autoreactive lymphocytes across the blood-brain barrier (BBB) may be responsible for axonal demyelination of neurons. In this review, we discuss microRNAs participating in the pathological processes of MS, including periphery inflammation, blood-brain barrier disruption, and CNS lesions, and in its therapeutic response, in order to find biomarkers of disease severity and to predict the response to therapy of the diseases.

Isoflurane Is More Deleterious to Developing Brain Than Desflurane: The Role of the Akt/GSK3β Signaling Pathway

Demand is increasing for safer inhalational anesthetics for use in pediatric anesthesia. In this regard, researchers have debated whether isoflurane is more toxic to the developing brain than desflurane. In the present study, we compared the effects of postnatal exposure to isoflurane with those of desflurane on long-term cognitive performance and investigated the role of the Akt/GSK3β signaling pathway. Postnatal day 6 (P6) mice were exposed to either isoflurane or desflurane, after which the phosphorylation levels of Akt/GSK3β and learning and memory were assessed at P8 or P31. The phosphorylation levels of Akt/GSK3β and learning and memory were examined after intervention with lithium. We found that isoflurane, but not desflurane, impaired spatial learning and memory at P31. Accompanied by behavioral change, only isoflurane decreased p-Akt (ser473) and p-GSK3β (ser9) expressions, which led to GSK3β overactivation. Lithium prevented GSK3β overactivation and alleviated isoflurane-induced cognitive deficits. These results suggest that isoflurane is more likely to induce developmental neurotoxicity than desflurane in context of multiple exposures and that the Akt/GSK3β signaling pathway partly participates in this process. GSK3β inhibition might be an effective way to protect against developmental neurotoxicity.

Role of sICAM-1 and sVCAM-1 as biomarkers in early and late stages of schizophrenia

Schizophrenia (SZ) is a neuroprogressive disorder presenting with biochemical, functional, and structural changes, which differ from early to late stages of the illness. We explored the differences in serum levels of soluble intercellular cell adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) between early and late stages of SZ, in regard to clinical characteristics and treatment application. Serum levels of sICAM-1 and sVCAM-1 were measured in 80 patients with SZ (40 early stage; 40 late stage), and compared with 80 healthy controls, matched by age, gender, body mass index, and smoking habits with each SZ group. Serum levels of sICAM-1 and sVCAM-1 were measured using ELISA. The severity of psychopathology was assessed using the Clinical Global Impression Scale and five-factor Positive and Negative Symptoms in Schizophrenia Scale. After adjustment for confounders, we noticed normal levels of sICAM-1 in the early stage, and elevated levels of sICAM-1 in the late stage of SZ. sVCAM-1 levels were decreased in both stages of SZ. Higher sICAM-1 levels have been related to more pronounced cognitive deficit and excitement symptoms in the early stage of SZ and to favorable characteristics of treatment application in both stages. SZ is associated with changes in the levels of adhesion molecules that vary from early to late stages of the illness. This implies that the concept of biochemical staging is applicable in SZ, at least for markers of cellular adhesion.

miR-98 and let-7g* protect the blood-brain barrier under neuroinflammatory conditions

Pathologic conditions in the central nervous system, regardless of the underlying injury mechanism, show a certain level of blood-brain barrier (BBB) impairment. Endothelial dysfunction is the earliest event in the initiation of vascular damage caused by inflammation due to stroke, atherosclerosis, trauma, or brain infections. Recently, microRNAs (miRNAs) have emerged as a class of gene expression regulators. The relationship between neuroinflammation and miRNA expression in brain endothelium remains unexplored. Previously, we showed the BBB-protective and anti-inflammatory effects of glycogen synthase kinase (GSK) 3β inhibition in brain endothelium in in vitro and in vivo models of neuroinflammation. Using microarray screening, we identified miRNAs induced in primary human brain microvascular endothelial cells after exposure to the pro-inflammatory cytokine, tumor necrosis factor-α, with/out GSK3β inhibition. Among the highly modified miRNAs, let-7 and miR-98 were predicted to target the inflammatory molecules, CCL2 and CCL5. Overexpression of let-7 and miR-98 in vitro and in vivo resulted in reduced leukocyte adhesion to and migration across endothelium, diminished expression of pro-inflammatory cytokines, and increased BBB tightness, attenuating barrier 'leakiness' in neuroinflammation conditions. For the first time, we showed that miRNAs could be used as a therapeutic tool to prevent the BBB dysfunction in neuroinflammation.

Tumour necrosis factor-α-mediated disruption of cerebrovascular endothelial barrier integrity in vitro involves the production of proinflammatory interleukin-6

The co-involvement of tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) during blood-brain barrier (BBB) injury has been reported in various models of neuroinflammation, although the precise functional interplay between these archetypal proinflammatory cytokines remains largely undefined within this context. In the current paper, we tested the hypothesis that TNF-α-mediated BBB disruption is measurably attributable in-part to induction of microvascular endothelial IL-6 production. In initial experiments, we observed that treatment of human brain microvascular endothelial cells (HBMvECs) with TNF-α (0-100 ng/mL, 0-24 h) robustly elicited both time- and dose-dependent induction of IL-6 expression and release, as well as expression of the IL-6 family receptor, GP130. Further experiments demonstrated that the TNF-α-dependent generation of reactive oxygen species, down-regulation of adherens/tight junction proteins, and concomitant elevation of HBMvEC permeability, were all significantly attenuated by blockade of IL-6 signalling using either an anti-IL-6 neutralizing antibody or an IL-6 siRNA. Based on these observations, we conclude that TNF-α treatment of HBMvECs in vitro activates IL-6 production and signalling, events that were shown to synergize with TNF-α actions to elicit HBMvEC permeabilization. These novel findings offer a constructive insight into the specific contribution of downstream cytokine induction to the injurious actions of TNF-α at the BBB microvascular endothelium interface. The co-involvement of tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) during blood-brain barrier (BBB) injury has been widely reported. Using human brain microvascular endothelial cells (HBMvEC), we show that TNF-α-mediated BBB disruption is measurably attributable in-part to induction of endothelial IL-6 production and signalling. We demonstrate that the TNF-α-dependent generation of reactive oxygen species (ROS), down-regulation of interendothelial junctions, and concomitant elevation of HBMvEC permeability, could be significantly attenuated by using either an IL-6 neutralizing antibody or an IL-6-specific siRNA. These findings provide insight into the complex nature of proinflammatory cytokine injury at the BBB microvascular endothelium interface.

Craniula: A cranial window technique for prolonged imaging of brain surface vasculature with simultaneous adjacent intracerebral injection

Background

Imaging of the brain surface vasculature following inflammatory insults is critical to study structural and functional changes in the living brain under normal and pathological conditions. Although there have been published reports relating to the changes that occur in the blood brain barrier (BBB) during the inflammatory process, the ability to visualize and track such changes in vivo and over time has proven to be problematic. Different techniques have been used to achieve visualization of pial vessels, but the approach has limits, which can jeopardize the well-being of the animals. Development of the cranial window technique provided a major advance in the acquisition of live images of the brain vasculature and its response to different insults and treatments.

Methods

We describe in detail a protocol for delivery of a localized inflammatory insult to the mouse brain via a craniula (cranial window and adjacent cannula) and subsequent imaging of the mouse brain vasculature by intravital microscopy and two-photon laser scanning microscopy. The surgical implantation of the craniula can be completed in 30-45 min and images can be acquired immediately and for several months thereafter. The technique is minimally invasive and permits serial injections directly to the brain, thereby allowing longitudinal imaging studies. The craniula technique permits the study of structural and functional changes of the BBB following inflammatory insult and as such has wide application to neuroscience research.

Protective Effects of Kaempferol against Myocardial Ischemia/Reperfusion Injury in Isolated Rat Heart via Antioxidant Activity and Inhibition of Glycogen Synthase Kinase-3β

Objective. This study aimed to evaluate the protective effect of kaempferol against myocardial ischemia/reperfusion (I/R) injury in rats. Method. Left ventricular developed pressure (LVDP) and its maximum up/down rate (±dp/dt_max) were recorded as myocardial function. Infarct size was detected with 2,3,5-triphenyltetrazolium chloride staining. Cardiomyocyte apoptosis was determined using terminal deoxynucleotidyl nick-end labeling (TUNEL). The levels of creatine kinase (CK), lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione/glutathione disulfide (GSH/GSSG) ratio, and tumor necrosis factor-alpha (TNF-α) were determined using enzyme linked immunosorbent assay (ELISA). Moreover, total glycogen synthase kinase-3β (GSK-3β), phospho-GSK-3β (P-GSK-3β), precaspase-3, cleaved caspase-3, and cytoplasm cytochrome C were assayed using Western blot analysis. Results. Pretreatment with kaempferol significantly improved the recovery of LVDP and ±dp/dt_max, as well as increased the levels of SOD and P-GSK-3β and GSH/GSSG ratio. However, the pretreatment reduced myocardial infarct size and TUNEL-positive cell rate, as well as decreased the levels of cleaved caspase-3, cytoplasm cytochrome C, CK, LDH, MDA, and TNF-α. Conclusion. These results suggested that kaempferol provides cardioprotection via antioxidant activity and inhibition of GSK-3β activity in rats with I/R.

Cultured cells of the blood-brain barrier from apolipoprotein B-100 transgenic mice: effects of oxidized low-density lipoprotein treatment

BACKGROUND

The apolipoprotein B-100 (ApoB-100) transgenic mouse line is a model of human atherosclerosis. Latest findings suggest the importance of ApoB-100 in the development of neurodegenerative diseases and microvascular/perivascular localization of ApoB-100 protein was demonstrated in the cerebral cortex of ApoB-100 transgenic mice. The aim of the study was to characterize cultured brain endothelial cells, pericytes and glial cells from wild-type and ApoB-100 transgenic mice and to study the effect of oxidized low-density lipoprotein (oxLDL) on these cells.

METHODS

Morphology of cells isolated from brains of wild type and ApoB-100 transgenic mice was characterized by immunohistochemistry and the intensity of immunolabeling was quantified by image analysis. Toxicity of oxLDL treatment was monitored by real-time impedance measurement and lactate dehydrogenase release. Reactive oxygen species and nitric oxide production, barrier permeability in triple co-culture blood-brain barrier model and membrane fluidity were also determined after low-density lipoprotein (LDL) or oxLDL treatment.

RESULTS

The presence of ApoB-100 was confirmed in brain endothelial cells, while no morphological change was observed between wild type and transgenic cells. Oxidized but not native LDL exerted dose-dependent toxicity in all three cell types, induced barrier dysfunction and increased reactive oxygen species (ROS) production in both genotypes. A partial protection from oxLDL toxicity was seen in brain endothelial and glial cells from ApoB-100 transgenic mice. Increased membrane rigidity was measured in brain endothelial cells from ApoB-100 transgenic mice and in LDL or oxLDL treated wild type cells.

CONCLUSION

The morphological and functional properties of cultured brain endothelial cells, pericytes and glial cells from ApoB-100 transgenic mice were characterized and compared to wild type cells for the first time. The membrane fluidity changes in ApoB-100 transgenic cells related to brain microvasculature indicate alterations in lipid composition which may be linked to the partial protection against oxLDL toxicity.

Activation of Cannabinoid Type Two Receptors (CB2) Diminish Inflammatory Responses in Macrophages and Brain Endothelium

Chronic neuroinflammatory disorders (such as HIV associated neurodegeneration) require treatment that decreases production of inflammatory factors by activated microglia and macrophages and protection of blood brain barrier (BBB) injury secondary to activation of brain endothelium. Cannabioid type 2 receptor (CB2) is highly expressed on macrophages and brain microvasular enndothelial cells (BMVEC) and is upregulated in inflammation and HIV infection. It has been shown that CB2 activation dampened inflammatory responses in macrophages and BMVEC. In this study, we assessed by PCR array the expression of a wide range of genes increased in macrophages and BMVEC in inflammation. TNFα treatment upregulated 33 genes in primary human BMVEC, and two highly selective CB2 agonists diminished expression of 31 and 32 genes. These results were confirmed by functional assays (BBB protection after inflammatory insult and decreased migration of monocytes across BMVEC monolayers after CB2 stimulation). Similarly, CB2 stimulation in primary human macrophages led to the suppression of 35 genes out of the 50 genes upregulated by LPS. Such changes in gene expression paralleled diminished secretion of proinflammatory factors. These results indicate the potential utility of CB2 agonists for the treatment of neuroinflammation.

Glycogen synthase kinase-3β inhibition in the medial prefrontal cortex mediates paradoxical amphetamine action in a mouse model of ADHD

Psychostimulants show therapeutic efficacy in the treatment of attention-deficit hyperactivity disorder (ADHD). It is generally assumed that they ameliorate ADHD symptoms via interfering with monoaminergic signaling. We combined behavioral pharmacology, neurochemistry and molecular analyses to identify mechanisms underlying the paradoxical calming effect of amphetamine in low trait anxiety behavior (LAB) mice, a novel multigenetic animal model of ADHD. Amphetamine (1 mg/kg) and methylphenidate (10 mg/kg) elicited similar dopamine and norepinephrine release in the medial prefrontal cortex (mPFC) and in the striatum of LAB mice. In contrast, amphetamine decreased, while methylphenidate increased locomotor activity. This argues against changes in dopamine and/or norepinephrine release as mediators of amphetamine paradoxical effects. Instead, the calming activity of amphetamine corresponded to the inhibition of glycogen synthase kinase 3β (GSK3β) activity, specifically in the mPFC. Accordingly, not only systemic administration of the GSK3β inhibitor TDZD-8 (20 mg/kg), but also local microinjections of TDZD-8 and amphetamine into the mPFC, but not into the striatum, decreased locomotor activity in LAB mice. Amphetamine effects seem to depend on NMDA receptor signaling, since pre- or co-treatment with MK-801 (0.3 mg/kg) abolished the effects of amphetamine (1 mg/kg) on the locomotion and on the phosphorylation of GSK3β at the level of the mPFC. Taken together, the paradoxical calming effect of amphetamine in hyperactive LAB mice concurs with a decreased GSK3β activity in the mPFC. This effect appears to be independent of dopamine or norepinephrine release, but contingent on NMDA receptor signaling.

Lower phosphorylated glycogen synthase kinase-3B levels in platelets of patients with schizophrenia: increment by olanzapine treatment

Glycogen synthase kinase-3B (GSK-3B) is involved with important neuronal processes such as cell survival, gene regulation, mood and cognitive performance. This enzyme is inactivated by phosphorylation at the phospho-Ser9 site. We compared GSK-3B levels in patients with schizophrenia to a health control group. The levels of phosphorylated and total GSK-3B in platelets of ten drug-free patients, ten long-term olanzapine treated patients and 20 healthy controls were determined by means of an enzyme immunoassay kit. In drug-free patients, GSK-3B levels were accessed again after 8 weeks on treatment with olanzapine. At baseline, drug-free patients presented lower phosphorylated and total GSK-3B levels than healthy controls (p < 0.05). After 8 weeks on olanzapine treatment, phosphorylated and total GSK-3B levels were significantly increased (p < 0.01). Reduced phospho-Ser9-GSK-3B in schizophrenia may disrupt signal-transduction pathways and influence crucial cellular processes, such as transcription, apoptosis, stress response and cell proliferation. Further studies should clarify whether the increment of GSK-3B phosphorylation by olanzapine is related to its antipsychotic effects.

Integrative proteomics and targeted transcriptomics analyses in cardiac endothelial cells unravel mechanisms of long-term radiation-induced vascular dysfunction

Epidemiological data from radiotherapy patients show the damaging effect of ionizing radiation on heart and vasculature. The endothelium is the main target of radiation damage and contributes essentially to the development of cardiac injury. However, the molecular mechanisms behind the radiation-induced endothelial dysfunction are not fully understood. In the present study, 10-week-old C57Bl/6 mice received local X-ray heart doses of 8 or 16 Gy and were sacrificed after 16 weeks; the controls were sham-irradiated. The cardiac microvascular endothelial cells were isolated from the heart tissue using streptavidin-CD31-coated microbeads. The cells were lysed and proteins were labeled with duplex isotope-coded protein label methodology for quantification. All samples were analyzed by LC-ESI-MS/MS and Proteome Discoverer software. The proteomics data were further studied by bioinformatics tools and validated by targeted transcriptomics, immunoblotting, immunohistochemistry, and serum profiling. Radiation-induced endothelial dysfunction was characterized by impaired energy metabolism and perturbation of the insulin/IGF-PI3K-Akt signaling pathway. The data also strongly suggested premature endothelial senescence, increased oxidative stress, decreased NO availability, and enhanced inflammation as main causes of radiation-induced long-term vascular dysfunction. Detailed data on molecular mechanisms of radiation-induced vascular injury as compiled here are essential in developing radiotherapy strategies that minimize cardiovascular complications.

Poly(ADP-ribose) polymerase-1 inhibition in brain endothelium protects the blood-brain barrier under physiologic and neuroinflammatory conditions

Blood-brain barrier (BBB) dysfunction seen in neuroinflammation contributes to mortality and morbidity in multiple sclerosis, encephalitis, traumatic brain injury, and stroke. Identification of molecular targets maintaining barrier function is of clinical relevance. We used a novel in vivo model of localized aseptic meningitis where tumor necrosis factor alpha (TNFα) was introduced intracerebrally and surveyed cerebral vascular changes and leukocyte-endothelium interactions by intravital videomicroscopy. Poly(ADP-ribose) polymerase-1 (PARP) inhibition significantly reduced leukocyte adhesion to and migration across brain endothelium in cortical microvessels. PARP inactivation diminished BBB permeability in an in vivo model of systemic inflammation. PARP suppression in primary human brain microvascular endothelial cells (BMVEC), an in vitro model of BBB, enhanced barrier integrity and augmented expression of tight junction proteins. PARP inhibition in BMVEC diminished human monocyte adhesion to TNFα-activated BMVEC (up to 65%) and migration (80-100%) across BBB models. PARP suppression decreased expression of adhesion molecules and decreased activity of GTPases (controlling BBB integrity and monocyte migration across the BBB). PARP inhibitors down-regulated expression of inflammatory genes and dampened secretion of pro-inflammatory factors increased by TNFα in BMVEC. These results point to PARP suppression as a novel approach to BBB protection in the setting of endothelial dysfunction caused by inflammation.

GSK3β is increased in adipose tissue and skeletal muscle from women with gestational diabetes where it regulates the inflammatory response

Infection and inflammation, through their ability to increase pro-inflammatory cytokines and chemokines and adhesion molecules, are thought to play a central role in the pathophysiology of insulin resistance and type 2 diabetes. Recent studies have shown that glycogen synthase kinase 3 (GSK3) plays a central role in regulating this inflammation. There are, however, no studies on the role of GSK3 in pregnancies complicated by gestational diabetes mellitus (GDM). Thus, the aims of this study were (i) to determine whether GSK3 is increased in adipose tissue and skeletal muscle from women with GDM; and (ii) to investigate the effect of GSK3 inhibition on inflammation in the presence of inflammation induced by bacterial endotoxin lipopolysaccharide (LPS) or the pro-inflammatory cytokine IL-1β. Human omental adipose tissue and skeletal muscle were obtained from normal glucose tolerant (NGT) women and BMI-matched women with diet-control GDM at the time of Caesarean section. Western blotting was performed to determine GSK3 protein expression. Tissue explants were performed to determine the effect of the GSK3 inhibitor CHIR99021 on markers of inflammation. When compared to women with NGT, omental adipose tissue and skeletal muscle obtained from women with diet-controlled GDM had significantly higher GSK3β activity as evidenced by a decrease in the expression of GSK3β phosphorylated at serine 9. The GSK3 inhibitor CHIR99021 significantly reduced the gene expression and secretion of the pro-inflammatory cytokines TNF-α, IL-1β and IL-6; the pro-inflammatory chemokines IL-8 and MCP-1; and the adhesion molecules ICAM-1 and VCAM-1 in tissues stimulated with LPS or IL-1β. In conclusion, GSK3 activity is increased in GDM adipose tissue and skeletal muscle and regulates infection- and inflammation-induced pro-inflammatory mediators.

P2X4 receptor regulates alcohol-induced responses in microglia

Mounting evidence indicates that alcohol-induced neuropathology may result from multicellular responses in which microglia cells play a prominent role. Purinergic receptor signaling plays a key role in regulating microglial function and, more importantly, mediates alcohol-induced effects. Our findings demonstrate that alcohol increases expression of P2X4 receptor (P2X4R), which alters the function of microglia, including calcium mobilization, migration and phagocytosis. Our results show a significant up-regulation of P2X4 gene expression as analyzed by real-time qPCR (***p < 0.002) and protein expression as analyzed by flow cytometry (**p < 0.004) in embryonic stem cell-derived microglial cells (ESdM) after 48 hours of alcohol treatment, as compared to untreated controls. Calcium mobilization in ethanol treated ESdM cells was found to be P2X4R dependent using 5-BDBD, a P2X4R selective antagonist. Alcohol decreased migration of microglia towards fractalkine (CX3CL1) by 75 % following 48 h of treatment compared to control (***p < 0.001). CX3CL1-dependent migration was confirmed to be P2X4 receptor-dependent using the antagonist 5-BDBD, which reversed the effects as compared to alcohol alone (***p < 0.001). Similarly, 48 h of alcohol treatment significantly decreased phagocytosis of microglia by 15 % compared to control (*p < 0.05). 5-BDBD pre-treatment prior to alcohol treatment significantly increased microglial phagocytosis (***p < 0.001). Blocking P2X4R signaling with 5-BDBD decreased the level of calcium mobilization compared to ethanol treatment alone. These findings demonstrate that P2X4 receptor may play a role in modulating microglial function in the context of alcohol abuse.

Inactive GSK3β is disturbed in the spinal cord during experimental autoimmune encephalomyelitis, but rescued by stem cell therapy

Glycogen synthase kinase 3β (GSK3β) is known to control neuroinflammation, however the status of GSK3β in multiple sclerosis, the most common inflammatory demyelinating disease of the CNS, and its animal model EAE, is unknown. In this study, we investigated the expression of phosphorylated GSK3β, the inactive form of GSK3β, in the spinal cords of EAE mice. We demonstrate that while the expression of phosphorylated GSK3β was present in radial astrocytes and neurons of the control mice that received only complete Freund's adjuvant, it was absent in radial astrocytes and significantly lower in neurons of EAE animals. The loss of phosphorylated GSK3β in radial glia and neurons in EAE spinal cords was concurrent with radial glia migration and astrogliosis. This disturbance in the expression of inactive GSK3β was recovered in neurons, but not in the radial glia, after treatment of EAE mice with adipose-derived mesenchymal stem cells capable of inducing a Th2 shift. Collectively, our results suggest a link between inactive GSK3β and modulation of the immune responses during EAE. Thus, we propose that maintenance of GSK3β in its inactive status may play a role in preserving the normal physiology of the spinal cord and amelioration of EAE following stem cell therapy.

Dynamic modulation of innate immune response by varying dosages of lipopolysaccharide (LPS) in human monocytic cells

Innate monocytes and macrophages can be dynamically programmed into distinct states depending upon the strength of external stimuli. Innate programming may bear significant relevance to the pathogenesis and resolution of human inflammatory diseases. However, systems analyses with regard to the dynamic programming of innate leukocytes are lacking. In this study, we focused on the dynamic responses of human promonocytic THP-1 cells to lipopolysaccharide (LPS). We observed that varying dosages of LPS differentially modulate the expression of selected pro- and anti- inflammatory mediators such as IL-6 and IL-33. Super-low dosages of LPS preferentially induced the pro-inflammatory mediator IL-6, while higher dosages of LPS induced both IL-6 and IL-33. Mechanistically, we demonstrated that super-low and high doses of LPS cause differential activation of GSK3 and Akt, as well as the transcription factors FoxO1 and CREB. Inhibition of GSK3 enabled THP-1 cells to express IL-33 when challenged with super-low dose LPS. On the other hand, activation of CREB with adenosine suppressed IL-6 expression. Taken together, our study reveals a dynamic modulation of monocytic cells in response to varying dosages of endotoxin, and may shed light on our understanding of the dynamic balance that controls pathogenesis and resolution of inflammatory diseases.